Hybrid vehicles potentially offer improvements to fuel efficiency and vehicle driving range over non-hybrid vehicles. One way to further improve fuel efficiency is to cease operating the engine. However, when engine operation is ceased, less than full torque output of the vehicle driveline may be available to avoid undesirable road conditions. Therefore, stopping engine rotation to conserve fuel may decrease the possibility that a driver will have a desired amount of driveline torque to avoid a particular road condition.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method of adjusting operation of a hybrid vehicle, comprising: adjusting a schedule for automatically stopping engine rotation in response to a condition of a driving surface.
By adjusting a schedule for automatically stopping an engine in response to driving surface conditions, it may be possible to reduce an amount if time between a request for additional wheel torque and the time torque is actually delivered to vehicle wheels. In one example, an engine may be allowed to idle decoupled from a vehicle driveline instead of coming to a complete stop when road conditions have degraded. Allowing the engine to idle avoids having to restart the engine. Consequently, torque output from the engine may be made available to the vehicle driveline in a more timely manner.
The present description may provide several advantages. Specifically, the approach may reduce an amount of time it takes to provide a higher wheel torque. Further, the approach may improve vehicle drivability. Further still, the approach may reduce driveline wear, thereby increasing the operating life of the driveline.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.